IMPORTANCE OF THE CUTANEOUS TRANSPIRATION. 73 



of which evaporation can take place, must acquire evapora- 

 tion takes 

 motion towards that membrane. place. 



The amount of this motion is directly propor- 

 tional to the rapidity of evaporation, and conse- 

 quently to the temperature and hygrometric state 

 of the atmosphere. 



That the skin of animals, and the cutaneous influence 



of the skin 



transpiration, as well as the evaporation from the and cuta- 

 neous 



internal surface of the lungs, exert an important transpira- 

 tion on 



influence on the vital processes, and thereby on the health. 



state of health, has been admitted by physicians ever 

 since medicine has existed ; but no one has hitherto 

 ascertained precisely in what way this happens. 



From what has gone before, it can hardly be Thecuta- 



. neous eva- 



doubted, that one of the most important functions poration 



has an im- 



of the skin consists in the share which it takes portant 

 in the motion and distribution of the fluids of the causing the 



T .. motion of 



body. the animal 



The surface of the body of a number of animals 

 consists of a covering or skin permeable for liquids, 

 from which, when, as in the case of the lung, it is 

 in contact with the atmosphere, an evaporation of j kin and 

 water, according to the hygrometric state and 

 temperature of the air, constantly goes on. 



If we now keep in mind, that every part of the This evapo- 

 ration must 

 body has to sustain the pressure of the atmosphere, produce 



and that the gaseous fluids and liquids contained in pressure ; 

 the body oppose to this pressure a perfectly equal 

 resistance, it is clear, that, by the evaporation of 

 the skin and lungs, and in consequence of the 



